How to join in a new thread when using stitch holders

How-to Questions
1

Hello!!
I am making my second sweater project. This was a sweater that started at the bottom and works up. The pattern called for stitch holders to hold the center and the left side of the sweater while you finish the right side. After doing that how do I join a thread to start knitting the back section? There is no tail of yarn to join to.

Thanks!!

2

You take a new end - either cut the one you were working with or use the other end of the skein or an end from a new skein.